A shape library can be saved and loaded to/from a file in XML-based format using the SaveToXml and LoadFromXml methods. The loaded shapes can be accessed through the Shapes property. They will be automatically added to the shared list of shapes kept in the Shape class, which lets you access them through the FromId method.

System.Object
    MindFusion.Diagramming.ShapeLibrary

ShapeLibrary Members
MindFusion.Diagramming Namespace